DC-to-DC converter, power converter, power generation system, and method for DC-to-DC conversion

Patent metadata

Field	Value
Publication number	US-9985545-B2
Application number	US-201715649792-A
Country	US
Kind code	B2
Filing date	Jul 14, 2017
Priority date	Feb 5, 2015
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

A DC-to-DC converter includes a first switching circuit, a second switching circuit, a transformer positioned between an AC side of the first switching circuit and an AC side of the second switching circuit, an inductance element positioned between the transformer and at least one of the AC side of the first switching circuit and the AC side of the second switching circuit, and control circuitry that operates the first switching circuit and the second switching circuit. The control circuitry sets a predetermined operation ratio of the first switching circuit and the second switching circuit to each other, and adjusts, based on the predetermined operation ratio, a first operation period of the first switching circuit and a second operation period of the second switching circuit.

First claim

The invention claimed is:

1. A DC-to-DC converter, comprising:
a first switching circuit;
a second switching circuit;
a transformer positioned between an AC side of the first switching circuit and an AC side of the second switching circuit;
an inductance element positioned between the transformer and at least one of the AC side of the first switching circuit and the AC side of the second switching circuit; and
control circuitry configured to operate the first switching circuit and the second switching circuit,
wherein the control circuitry is configured to set a predetermined operation ratio of the first switching circuit and the second switching circuit to each other, and adjust, based on the predetermined operation ratio, a first operation period of the first switching circuit and a second operation period of the second switching circuit.

2. The DC-to-DC converter according to claim 1 , wherein the control circuitry is further configured to set the predetermined operation ratio based on reference power that is input from one of the first switching circuit and the second switching circuit or on reference power that is output from one of the first switching circuit and the second switching circuit.

3. The DC-to-DC converter according to claim 2 , wherein the control circuitry is further configured to set a non-reference operation ratio of the first switching circuit and the second switching circuit to each other based on the predetermined operation ratio and based on non-reference power that is different from the reference power and that is input into one of the first and second switching circuits or is output from one of the first and second switching circuits, and adjust the first operation period of the first switching circuit and the second operation period of the second switching circuit based on the non-reference operation ratio.

4. The DC-to-DC converter according to claim 3 , wherein the control circuitry is further configured to calculate a first reference operation period of the first switching circuit and a second reference operation period of the second switching circuit based on the reference power input into or output from one of the first switching circuit and the second switching circuit, and change the first reference operation period and the second reference operation period based on a ratio specified by a power command to make the first operation period of the first switching circuit and the second operation period of the second switching circuit compliant with the power command.

5. The DC-to-DC converter according to claim 4 , wherein the control circuitry is further configured to calculate a square root ratio of the reference power and the power command to each other, and multiply the first and second reference operation periods of the first switching circuit and the second switching circuit, respectively, by the square root ratio calculated to obtain the first operation period of the first switching circuit and the second operation period of the second switching circuit.

6. The DC-to-DC converter according to claim 5 , wherein the operation ratio of the first switching circuit and the second switching circuit to each other, corresponds to a ratio of a first period, a second period, and a third period to each other, the first period being a period in which one of the first switching circuit and the second switching circuit, operate, the second period being a period in which the first switching circuit and the second switching circuit, operate, and the third period being a period in which one of the first switching circuit and the second switching circuit, operate, and the control circuitry is configured to cause a reference ratio of the first period, the second period, and the third period to each other, that is based on the reference power input into or output from the first switching circuit and the second switching circuit, to be same as another ratio of the first period, the second period, and the third period to each other, that is based on different power, the different power being different from the reference power and being input into or output from the first switching circuit and the second switching circuit, and adjust the first period, the second period, and the third period based on the resulting ratio.

7. The DC-to-DC converter according to claim 6 , wherein when the reference power is input into or output from the first switching circuit and the second switching circuit, the first period, the second period, and the third period are respectively initialized as a first reference operation period, a second reference operation period, and a third reference operation period, and the control circuitry is further configured to calculate the first reference operation period, the second reference operation period, and the third reference operation period based on a first voltage at a DC side of the first switching circuit and based on a second voltage at a DC side of the second switching circuit.

8. The DC-to-DC converter according to claim 7 , wherein the transformer comprises a first winding coil at a first side of the transformer closest to the first switching circuit, and a second winding coil at a second side of the transformer closest to the second switching circuit, the first winding coil and the second winding coil comprising a winding coil ratio of N:1, and the control circuitry is further configured to instruct storage of a minimal value of the first period and a minimal value of the third period, and determine the minimal value of the first period as the first reference operation period when the first voltage is more than N times the second voltage, and determine the minimal value of the third period as the third reference operation period when the first voltage is less than N times the second voltage.

9. The DC-to-DC converter according to claim 3 , wherein the operation ratio of the first switching circuit and the second switching circuit to each other, corresponds to a ratio of a first period, a second period, and a third period to each other, the first period being a period in which one of the first switching circuit and the second switching circuit, operate, the second period being a period in which the first switching circuit and the second switching circuit operate, and the third period being a period in which the one of the first switching circuit and the second switching circuit, operate, and the control circuitry is configured to cause a reference ratio of the first period, the second period, and the third period to each other, that is based on the reference power input into or output from the first switching circuit and the second switching circuit, to be same as a non-reference ratio of the first period, the second period, and the third period to each other, that is based on non-reference power, the non-reference power being different from the reference power and being input into or output from the first switching circuit and the second switching circuit, and adjust the first period, the second period, and the third period based on a resulting reference ratio.

10. The DC-to-DC converter according to claim 9 , wherein the control circuitry is further configured to determine the first period, the second period, and the third period as a first reference operation period, a second reference operation period, and a third reference operation period, respectively, when the reference power is input into or output from the first switching circuit and the second switching circuit, and obtain the first reference operation period, the second reference operation period, and the third reference operation period based on a first voltage at a DC side of the first switching circuit and based on a second v

Assignees

• Yaskawa Electric Corp

Inventors

• Fujisaki Seiji
• Ishii Sadao
• Ide Kozo

Classifications

• H02M3/3376

  with automatic control of output voltage or current · CPC title

• H02M3/33507

  with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence) · CPC title

• H02M3/33576 Primary

  having at least one active switching element at the secondary side of an isolation transformer · CPC title

• H02M1/0048

  Circuits or arrangements for reducing losses (using snubbers H02M1/34) · CPC title

• H02M3/28

  using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC · CPC title